In the core structure of air mattress and the like, an inflation is held down generally by an I-beam system (FIG. 3), X-beam system (FIG. 4) and deformed X-beam system (FIG. 5).
In case of producing a boat, mattress, life preserver and the like by filling air in its ,inside with leather cloth sheets produced by pasting the cloth sheet made of Nylon, cloth and the like and the sheet made of vinyl, urethane, rubber and the like together, in order to secure an air cushioned portion in a proper thickness by holding down its inflation, the upper and lower leather cloth sheets 3 were directly fused (FIGS. 4 and 5), or core members 4 were used which were produced by pasting both end portions of the core members to the upper and lower leather cloth sheets 3 by means of an adhesive (FIG. 3) whereby a core structure was produced. However, in the mattress and the like of the core structure by the conventional systems, when it was used for many years during which an anticipated load F was applied, the fused portion or the pasted together portion 10 was cut giving a cause of a leakage of air filled therein, and particularly, in case of using the core of the I-beam system, the pasted together portion (bonded surface) of the leather cloth sheet and the core member was peeled apart to lose the operation of holding down the inflation in some cases. Let us to explain this phenomenon by referring to FIG. 3, in which in case of the mattress of the I-beam structure, when the load F was applied to the upper portion of the mattress, force F' worked towards the outside around the periphery of an air chamber 8. Also, in case the load F was of magnitude more than the anticipated value, the force F' worked on the periphery of the air chamber 8 greatly. As a result, the bonded surface 10 of the core member 4 was peeled apart from the leather cloth sheet or the cut started from the pasted together portion. Also, in case of the mattress of the X-beam structure, similar to the I-beam system, when the load F was applied in the direction of the upper part, there was an apprehension that the force F' worked towards the outside around the periphery of the air chamber so that the fused surface 10 was broken to cause a leakage of air from the air chamber 8. The deformed X-beam structure had the similar drawback.
However, in the case of the air mattress, air pillow case and the like, the load F was not too big and also, the pneumatic pressure F' of the air chamber 8 was not required to be a high pressure so that the holding down of the inflation of an air cushioned portion could be materialized by the core structure of the conventional system, but the product required to have a high pneumatic pressure of the air chamber with extremely high load F was not suitable, for example, to be used as the core member in a buoyance adjusting apparatus for scuba diving, life preserver and the like.
This invention has been made in view of the foregoing points, and its object is to provide a core structure for air filled product capable of withstanding the large load and internal pressure.